In a typical cellular radio system, also referred to as a wireless communication system, user equipments, also known as mobile terminals and/or wireless terminals communicate via a Radio Access Network (RAN) to one or more core networks. The user equipments can be mobile stations or user equipment units such as mobile telephones also known as “cellular” telephones, and laptops with wireless capability, e.g. mobile termination, and thus can be, for example, portable, pocket, hand-held, computer-included, or car-mounted mobile devices which communicate voice and/or data with radio access network.
The radio access network covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g., a Radio Base Station (RBS), which in some networks is also called “eNB”, “NodeB” or “B node” and which in this document also is referred to as a base station. A cell is a geographical area where radio coverage is provided by the radio base station equipment at a base station site. The base stations communicate over the air interface operating on radio frequencies with the user equipment units within range of the base stations.
In some version of the radio access network, several base stations are typically connected, e.g., by landlines or microwave, to a Radio Network Controller (RNC). The radio network controller, also sometimes termed a Base Station Controller (BCS), supervises and coordinates various activities of the plural base stations connected thereto. The radio network controllers are typically connected to one or more core networks.
The radio access technologies for cellular mobile networks are continuously being evolved to meet the future demands for higher data rates, improved coverage and capacity. Examples of recent evolutions of the WCDMA access technology are HSPA (High-Speed Packet Access). Currently further evolutions of the 3G systems, 3G Long Term Evolution (LTE), including new access technologies and new architectures are being developed within the 3rd Generation Partnership Project (3GPP) standardization body among others with the aim to provide support for functions like inter cell load balancing, inter cell interference coordination, optimisation of mobility control (in case of hierarchical cell structures), distributed physical cell identity allocation/selection, etc.
All these functions require certain information about the characteristics and role of the neighbouring cells, information which could be provided to a base station, sometimes called NodeB or eNodeB, as part of information on a handover of a mobile terminal, sometimes called UE or mobile station e.g. together with UE History Information.
This however involves collecting a lot of statistical handover information as well and is not an especially quick or flexible procedure.
Cell type has been defined in 3GPP specification often as:
macro, micro, pico, femto [1];
large, (medium), small [2];
wide area, (medium area), local area [3].
The size of the cell coverage area and the cell hierarchy level may but are not necessarily coupled, e.g. two cells may both have large coverage area but depending on the purpose in the radio network, those two cells may belong to different level in cell hierarchy.